
 
/*侧边栏选择器*/
.sidenav {
    height: 300px;
    width: 0; /*原始宽度*/
    position: fixed;
    /*z-index、top、left共同控制侧栏的悬浮（上方1，下方-1）*/
    z-index: 1;
    top: 210px;
    left: 0;
    background-color: lightblue;
    overflow-x: hidden;
    transition: 0.5s; /*侧栏延迟0.5s显示*/
    padding-top: 60px;
}
 
/*侧边栏标签选择器*/
.sidenav a {
    padding: 8px 8px 8px 32px;
    text-decoration: none;
    font-size: 25px;
    color: #818181;
    display: block;
    transition: 0.3s; /*标签延迟0.3s显示*/
}
 
/*侧栏标签和关闭按钮光标的效果*/
.sidenav a:hover, .offcanvas a:focus{
    color: #f1f1f1;
}
 
/*侧栏和关闭按钮的位置选择器*/
.sidenav .closebtn {
    position: absolute;
    top: 0;
    right: 25px;
    font-size: 36px;
    margin-left: 50px;
}
 
/*主体内容*/
#main {
    left:0;
    top:0;
    width:100px;
    /*transition: margin-left .5s;/*主体内容延迟0.5s整体y右移动*/
    padding: 16px;
}
 
/*当文档高度小于450px时，改变侧栏的padding属性和字体大小*/
@media screen and (max-height: 450px) {
  .sidenav {padding-top: 15px;}
  .sidenav a {font-size: 18px;}
}